The present invention relates to electrical busway apparatus, and particularly to an improved, plug-in busway and compatible bus plug.
Modern electrical busway design typically calls for the bus bars to be individually insulated and arranged in side-by-side, sandwiched relation within a close-fitting housing. This affords an extremely compact design and also promotes a cool running busway since the housing can act as a large heat sink. At each end of the busway sections, the bus bars are typically spread apart or "fanned out" to provide laterally spaced terminal portions which facilitate the making of electrical joints between busway sections. Exemplary of this approach is the disclosure in commonly assigned U.S. Pat. No. 3,365,537. Our commonly assigned U.S. Pat. No. 3,882,265 discloses an alternative approach which does not require fanning of the bus bar terminal end portions at the ends of busway sections. Rather, the bus bar terminal end portions are provided with a longitudinally staggered array of individual scarf lap joint halves which are clamped in electrical connection with a complementary staggered array of individual scarf lap joint halves provided in the bus bar terminal end portions of an adjacent busway section, pursuant to joining two sections end-to-end.
Another situation typically calling for lateral separation of the sandwiched bus bars is where a power take-off device, such as a busway plug, is to be tapped into a busway section. This approach, as represented by the disclosure of commonly assigned U.S. Pat. No. 3,384,856, accommodates electrical engagement of the take-off device stabs with the individual bus bars while conveniently affording electrical isolation between phases. An alternative approach, disclosed in U.S. Pat. No. 3,744,002, maintains the sandwiched relationship of the bus bars while preserving phase isolation by appropriately notching the edges of the bus bars so that the plug stabs can reach in to electrically engage the edge portions of individual bus bars without contacting the other bus bars. U.S. Pat. No. 3,178,668 discloses still another approach, wherein bus plug stabs of varying lengths extend through clearance holes in some of the bus bars and into abutting electrical contacting engagement with the planar surfaces of appropriate individual bus bars.
It is an object of the present invention to provide improved electrical busway apparatus.
A further object is to provide an improved plug-in busway and bus plug therefor.
An additional object of the present invention is to provide plug-in busway wherein the bus bars remain in sandwiched relation, and yet are capable of accommodating a bus plug.
Yet another object of the present invention is to provide the combination of an improved plug-in busway and an improved bus plug, wherein proper phasing is maintained irrespective of from which side of the busway the plug is plugged in.
A still further object is to provide a plug-in busway and bus plug of the above character which are inexpensive to manufacture, convenient to implement and capable of providing a compact electrical joint.
Other objects of the invention will in part be obvious and in part appear hereinafter.